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who has the quietest side pipes and how.

33K views 64 replies 36 participants last post by  David Borden 
#1 ·
I have seen many posts on how to get the "bite" out of the sidepipes.
Inserts, quitpipes, classic chamber etc.....

My goal is to get my car as quiet as possible even to the level of a DD.
At 2000 rpm's cruising at ear level I am at 90db.
Who has the quietest sidepipes and how did you do it.
Looking for inexpensive options.


john
 
#2 ·
I did some under the hood Magnaflows that were too quiet. They would rival many high performance cars stock exhaust on sound. I could have easily ran the pipe down the side of the car instead of the short dump.



 
#27 ·
I did some under the hood Magnaflows that were too quiet. They would rival many high performance cars stock exhaust on sound. I could have easily ran the pipe down the side of the car instead of the short dump.
Are the videos posted above with the mufflers that are TOO QUIET ????
 
#5 · (Edited)
I've been thinking a lot about exhaust and how glass packs have to be replaced because they get burned out. I research a lot of interesting, composite materials and one that has caught my attention is aerogel's pyrogel. It's an insulation material designed to stand up to 1300*F and drastically cut down on the temp seen on the other side. It's based on glass mats and it's hydrophobic yet breathable. So I think it would be a perfect replacement for traditional glass packing but I haven't had the opportunity to try it. I could see this replacing glass packing for good, without need of replacing it and with a ceramic coating like Jet Hot, reduce side pipe temps to safe levels.

How will this help sound? Not too sure, that all depends on muffler design. I have heard from more than one person that angling the tips down a little bit helps. My main interest is in minimum flow restriction. Just something to think about, for anyone interested in side pipe options.
 
#6 · (Edited)
Dynatech Auger Inserts

I have had these installed for about 9 months now and am very pleased with the results, throaty sound but not boomy and 6 dbA reduction in cockpit sound level.

Trip to Huntington in April did not require ear plugs at all, wind noise is the loudest thing now. Around town you can hear the stereo until wind noise takes over, this is only a 4x75 watt system.

Cost was about $400 in materials (stainless pipes, about $200 for painted) and some cutting and welding which I did, a machine shop would probably do all of it for $125...not rocket science.

Here's the origninal post:

http://www.ffcars.com/forums/17-fac...-exhaust-mod-time-dynatech-auger-inserts.html

Packing is holding up great, I probably have another 3 repacks left for the $35 I paid for the roll of Ceramic wool from McMaster Carr.

Appearance is a bit of an issue if you don't have heat shields...these are Drummer Mikes that I customized with slots:
 

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#7 ·
SJDave,

I like those Vibrant Flanges. How well do they seal?

I saw it was a MIG welder that you used but what kind of wire did you weld the SS flanges with?

There is a recent article in Grassroots Motorsports, Nov 2014, p. 139 that discusses repacking a sealed muffler. They used muffler packing material from Bristol Core, Inc. They state that short strand fiberglass can find its way out of the packing, while, the more expensive, long stand will last longer. They were able to lower the decibels by 5 simply by repacking the muffler and they suspect that they gained a bit of power at certain resonance points.

I was leaning toward the Classic Chambers fix that Bob Cowan did but I'm considering this fix on the Stainless pipes I have.

I like those Drummer Mikes heat shields with the slots.

George
 
#8 ·
They seal really really well, no sign of exhaust leakage out the flanges under the band clamp. The clamp is very secure high quality piece made for diesel turbo systems.

But.... since I step welded the flanges into the pipes, there is a bit of minor leakage between the welds. Next time I take the tips off I am just going to use some Copper RTV to seal the gaps in the weld.

TIG would make it a whole lot easier, especially grinding off the excess on the inside on the baffle side of the sidepipe.

I used a stainless wire recommended by the guys at the local Airgas shop and a Tri Mix Gas... 90%Helium,7.5% Argon,2.5%C02. I am a hobbyest welder, so it shows.

It took me about 8 hours to slot both covers on the Bridgeport...was out of work... so my time was free and abundant...and I was looking for something to do! My Mill is Manual, but has a power feed and digital readouts which helped alot. I like them slotted alot...but it's personal preference.
 

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#9 · (Edited)
A Different Solution

I too wanted to quiet the sound level from the exhaust. My solution has two parts, CAT/J-pipes and Gas-N sidepipes. I used the CAT/J-pipe as a pre-muffler before the sidepipes. The Gas-N sidepipes are somewhat quieter than the FF pipes as well. Together, the car is still louder than a DD, but I can communicate with my passenger when not accelerating. Under acceleration, the car has a exhaust note that is appropriate for what it is. Neither myself nor my wife have felt the need for ear plugs as yet. As noted by others, on the highway, wind noise exceeds the exhaust noise most of the time anyway. Yes I lose some HP with this setup, but still better than the OEM exhaust setup from Ford for my 4.6L DOHC engine.

Alan
 
#10 ·
Cats

I have the FFR catalytic converters with their side pipes and really like the sound. It's plenty loud above 3000 RPM when you want it. Under that it's quiet enough to drive through neighborhoods without alarming anyone. I use earplugs only for wind noise on the highway.
 
#11 ·
Breeze Quiet Pipes

These worked for me. At 70 mph the absolute majority of the noise is from the wind, at least according to my Radio Shack meter. The pipes are probably restrictive enough to rob me of some horsepower, but I can still scare the c..p out of myself with what's left.
 
#15 ·
X2. This is the quickest and easiest solution. My Breeze pipes are quieter than any other Cobra I've heard. I drive a lot.
 
#14 ·
Anyone has used classic chamber 2.5" ?
There is a member here who has used them. I think the best thing you can do right now is go out and do some dB recordings of your Cobra. Then figure out roughly how much you want to reduce that by. That will give you a direction to decide on what products / ideas to use based off of what people have seen in dB reduction. Do a cockpit dB at various RPM levels and then from like 15 ft.
 
#17 ·
At about 50-60,000 miles the "bark" at acceleration became uncomfortable for us.
Stock 302. I am sure all the muffler control was long gone by then.

The simple and affordable CC Inserts into the "J" pipe solved that problem. With the CC Inserts shoved into place, I took the "J" pipes to the muffler shop for a couple quick spot welds to hold them. Easy to remove if I decided they were not the solution.

15-20,000 miles later, they were the right call for our issues. Trips are much more enjoyable and comfortable.
 
#18 ·
I had heard great things about the product, but what I received was nothing like what I had seen in reviews or on their web site. According to CC, their supplier had changed manufacturing process but they hadn't updated their web site. They switched from a nice louvered core to a much cheaper and less effective punched core like what's used on very cheap glass pack style mufflers. All of this happened about two months ago and they could not provide me with their old style product. Basically they designed and sold a good product and then pulled a bait and switch for more $$.

I'm now going to try and make something that's probably just like what you currently have.
 
#19 ·
I have nothing to compare them to, but I'm very happy with my Classic Chambered pipes, and at around $200, welding included, they are affordable. I went with 26" and installed them with the louvers facing the flow. Significant db reduction and much more pleasant tone.
 
#20 ·
#21 ·
I have UTC with a big Magnaflo X muffler in front and a pair of Sweet Thunder mufflers under the car. I am not stock quiet but well under max Db levels. It wasn't cheap prob about $1,500 to retrofit unless you have the welding skills to do the pipe work from headers back to foot boxes. I would do Mike's mufflers into your side pipes. It wont be too quiet.

Pic are at the bottom of pg 1 of my link below and then continued on pg 2.
 
#22 ·
I used classic chambered exhaust 30" or 32",cant remember, full packing and smallest I.D. faced the scoops to the airflow. Had to shorten the collectors and turnout to make it fit but looks good. Loud as blown out FFR units,loud as hell, very dissapointed. Made a bolt on baffle to knock down flow and just as loud but has a slight whistle now. Hype vs. reality, reality won and I lost.
 
#23 ·
#24 ·
A couple years back, a forum member posted his solution to quietness. He bought something at Home Depot that he modified and inserted up in exhaust turndown then screwed in through back of pipe. I've searched but can't seem to find key words. Anybody remember this?
 
#25 ·
#30 · (Edited)
I made a modified version of this. I bought the kitchen strainers, but I didn't like how they were going to fit so I returned them and used the plasma cutter to cut my own doughnuts. I used fine screen mesh (0.040 diameter wire) from McMaster and TIG welded everything together. I made the insert so that it was held tight by a set screw. My inserts are 4.5" long (as long as I could make them and still be able to make the turn on the turn out) and reduced my SPL by almost 3 dB (C weighted). I went from 100 dB with stock pipes and cats at idle to 97. I then took the design one step further and had a flighting company make me an auger to my spec that would fit inside the insert. I welded that in and the SPL at idle went to 94 dB (C weighted). However, the auger killed my throttle response. I noticed no decrease in power with the non-auger version of the insert. The ID of my insert is 2.125". I've been runing the non-auger version for several months and I'm in the middle of making new side pipes. My new pipes will take the insert idea a little further, I'm going to neck down to 2.5" right after the collecter with cones I purchase from Cone Engineering and have I'll have a small muffler between the collector and the glass pack. With the new pipes the insert at the turn out will be 6" long (currently 4.5") and it will be permanent. Basically my entire side pipe will be a flow through muffler. I'll be using 24" Classic Chambered mufflers in the center section. My goal is 94 dB or less at idle (a 6 dB decrease over stock pipes) with no noticable decrease in power or throttle response.

The total cost for the new pipes with ceramic coating will be about $900.

BTW I also went from J-pipes to cats and noticed no decrease in sound level. I did not measure the car with J-pipes though. The cats do get rid of the exhaust stink though.

Another possible solution is to make inserts that are similar to the core that Borla uses with several perforated tubes put together. My dad has a Valkyrie motorcycle that he purchased used. The previous owner removed the exhuast core and made it louder. My dad decided he wanted the bike quieter so he did some research and it turned out that Honda originally had inserts with several perforated tubes put together. Honda even had different size perforations at different locations. My dad made a prototype insert based on Honda's design and the sound was exactly what he as looking for. I've been thinking about trying a similar insert in my stock FFR mufflers just to see what it would do to the sound.

Wibby
 
#28 ·
Chambered Classics with a cross over.... nice!
 
#31 ·
I'll share my sidepipe/sound odyssey. Maybe it will help.

During the build, I knew that I didn't want to use the FFR pipes for a few reasons. First, I knew that the packing fairly quickly blew out. Second, I knew that they were raspy to the point of being painful at higher revs and finally, I knew that I wanted to autocross the car and our SCCA region has a fairly strict sound policy. The FFR pipes definitely wouldn't pass sound.

My first iteration was the Classic Chambered Cobra Packs. I got the 32" 2-1/2" ID packed mufflers. These are the quietest mufflers they make. For details on the retrofit, see here. Even with my crappy welding skills, they came out nicely. The advantage of welding them up yourself is that you can make them fit perfectly, obviating the need for wedges or spacers. I had them ceramic coated at NitroPlate. They look and sound great. They are definitely quieter than the FFR glasspacks, but I wouldn't say they were quiet.

Sadly, they weren't quiet enough for autocross. I was blowing 100dB as measured 50 feet perpendicular from the fastest part of the course where I was close to full throttle. So, back to the drawing board.

After a fairly thorough search of available mufflers, I came across these. They are 30" mufflers that are packed and contain two comes nose-to-nose. Two things made them attractive - the "mild to moderate" sound description, and the 3.5" ID flow path. So, I ordered a pair (they're not cheap) and also bought a used set of raw steel FFR pipes from the classifieds. I didn't want to cut up my Classic Chambered pipes after all the work I put into getting fit perfectly plus the cost I put into ceramic coating for them. So, I decided to build a second pair of pipes.

The Flowmasters make the job of building the pipes dead-nuts easy. Their ID is exactly the same 3.5" as the OD of the FFR pipe tubing. I simply cut the muffler out of the FFR pipes, leaving the collector and turnout. Both the collector and turnout slide perfectly into the Flowmaster mufflers. All it took was two easy weld beads and the pipes were done.

I have to say that the Flowmasters are very quiet, particularly at idle and cruise. They also have a nice deep rumble with no raspiness. They do, however, get pretty loud at WOT, and I have found that I will still bust sound at autocross occasionally.

So, I added one more modification. I bought a couple of exhaust turnouts that will slip over 3-1/2" tubing and cut the old turnouts off, leaving about a 2" stub of 3-1/2" tubing over which the new turnouts will slip. I then got a pair of 3-1/2" augers and found that will just a little fiddling and trimming, I could tack weld the augers to the inside of the turnout, and the rest of the auger would slip into the muffler. I riveted the turnouts into place (this is easily reversible and allow me to play with the turnout angle). The result was pretty amazing. The car is almost factory-car quiet - even at WOT. I'm sure there is a performance penalty, but my butt-dyno couldn't detect it.

So, the take-away from this lengthy post is that you can easily make some very quiet pipes that retain a decent flow path but using the Flowmaster mufflers referenced above with some augers inserted into the aft end. The augers could go in when you make the pipes up and be tack welded to both the muffler and the turnout to prevent rattling. I only left mine removable to give me options to meet sound at autocross.

Tim
 
#32 ·
Tim,

Great documentation, with links, of your work. Interesting sidepipe by Flowmaster.

I just called them regarding the packing. There is 'None'. Only an inner core that is perforated. Wow, they must have done some research to figure out to just perforate the pipe and make it run quieter.

There is an inner pipe with a diameter of 3.5" and the outer diameter of the muffler is 4.5" which makes an air space of 1/2" all the way around. :yes:

Interesting too that they state the outside of the pipe does not get as hot as the standard pipes out there. I do know that SS is very low in dissipation of heat so that inner core being SS is really working well to keep the transfer of heat through to the outer muffler shell.

From the Flowmaster site:
Flowmaster introduces its new Slimline sidepipe style mufflers. Intended for Shelby Cobra sidepipe applications, these Laminar Flow technology mufflers can be used in other applications and feature a raw 304S stainless steel case with no logos for a cleaner appearance. The inlet and outlet diameter is 3.50 with a 4.50 body and 30.00 long case. These mufflers offer a quieter alternative to the glasspack style mufflers that are traditionally used in these applications, plus the Cool Shell Technology helps prevent the outside of the muffler case from seeing the extreme temperatures associated with sidepipe applications. The Slimline mufflers are made in the USA and backed by Flowmasters Lifetime Limited Warranty.

✓ Stainless Steel Construction
✓ Quieter Alternative for Sidepipe Applications
✓ Patented Laminar Flow Technology
✓ Lifetime Limited Warranty

Application: Cobra sidepipe and custom street rod applications


What is cool about this solution is never having to repack the mufflers or ever having the sound change after a year or two.

Tim, do you have a picture of the turnout mounted and off with the auger installed?

George
 
#34 ·
Interesting too that they state the outside of the pipe does not get as hot as the standard pipes out there. I do know that SS is very low in dissipation of heat so that inner core being SS is really working well to keep the transfer of heat through to the outer muffler shell.
This is definitely true. They run much cooler than the FFR glasspacks. I can put my hand on them (briefly) without getting burned. You're right about no packing. I was thinking about my Classic Chambered mufflers.


GWL said:
Tim, do you have a picture of the turnout mounted and off with the auger installed?

George
I will try to take some tonight. They're currently off the car. I just got done painting them with VHT.

Tim
 
#33 ·
Sweet Thunder...

I shipped my side pipes off to Sweet Thunder and had them install their medium size chambered exhaust. Once I got them home I then ordered some Dynatech Vortex Cones and stuffed them with stainless steel Scott Brites. I'm happy with the sound... It is just right for an old man like me.
 
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